No, the code for the disks is not exclusive to either version. While the hard drives are different, the code to handle both types should exist in both versions. Otherwise the single bootloader that works for both wouldn't work.
Rockbox uses the extra memory to buffer more audio. That's really the only reasonable thing to do with it, from our perspective. We have no way of knowing how Apple uses it, and it's not really relevant here.
As well, this question is no longer in any way installation related.